Optimization of THz quantum cascade lasers with an active module based on two-quantum wells for high-temperature operation

Over the past two decades, the operation temperature of terahertz quantum cascade lasers (THz QCLs) has continuously increased from cryogenic level to the current record value of 250 K (about -23°C) [1]. Here we review the state-of-the-art and future prospects of high-temperature THz QCL designs with two-quantum wells in active module based on conventional heterojunction GaAs/AlGaAs and alternative material system HgCdTe. We have analyzed the temperature dependence of the peak gain and predicted the maximum operation temperatures of the given designs.